Manufacture of electric filaments.



' (LA! VON WELSB'AGH. MANUFACTURE OF ELECTRIC FILAMENTSM APPLIGATIQNFILED AUG. 9, 1898.

1,086,428, Patented F eb.10,1914.

manufacture of incandescents, that is electri- U O A CARL .AUER vouwnLsBAoH, or VIENNA, nus'riua-nmvcmnr, Assrenon. r'o WELS- 3 BACK LIGHTCOMPANY, or GLOUCESTER our, NEW JERSEY, A CORPORATION or NEW J SEY.

Application filed Au uste, 129s. Seria1'No.688,205.

To all whom it may concern Be it known that I, Dr. CARL trial-Hungary,residing at Vienna, Austria-- Hungary, haveinvented or discovered acertain new and useful Improvement in the Manufacture of Electric.Filaments, of which the following is a specification.

My invention relates to certain new and useful improvements in andrelating to the cally conducting bodies which in the form 'of filaments,or the like, are adapted to be traversed by an electriccurrent and toconvert the electric energy into light. I

- In carrying out my invention, I obtain as the final product anincandescent comprising a mixture of a metal and a metallic oxid insuchcondition that it will remain substantially stable under theordinary conditions to which it. is subjected when traversed by theelectric. current The metal employed is of such'char'acter as not tomelt or volatilize at the temperature to which the incandescent isbrought by the passage of the electric current' and the metallic oxidemployed 'is 'of such acharacter as to practically retain its oxygenrather than give it up in whole or in part "to the metallic constituentof the filament. 'I find that a mixture well adapted for this purpose isone consisting substan- 'tially of osmium and thoria' prepared inaccordance with the processes hereinafter set forth, these particularingredientspossessing the peculiar properties indicated to a very highdegree, particularly because of the fact. that thoria even at-very hightemperatures to which itwould be subjected has no tendency tovolatilization.

By means of my'invention, I produce an electric incandescent consistingof a mixture of a metal and an oxid of the characterreferred to, andwhich will remain stable, or substantially stable when brought, by thepassage of the electric current, to the in'can-' descing temperaturerequired for effectlve Speoiilcation'bf Letters Patent.

. AUER you, .WELSBAQH, a subjectof the Emperor of Ausmetal osmium or asuitable salt or salts MA UFACT RE or ELEcrRIc rrna vrnlvrs' Patentedthere-of, such as the sulfid, in'combination with thoria. Howeverruthenium or rhodium or their suitable salts either in whole or part maybe used in place of the osmium and the thoria' may be. replaced in wholeor part by zirc'onia-hereafter to be understood as lncluded Within theterm rare earths or the yttrite earths. I will proceed to describe amethod of practically utilizing my preferred mixture of osmium andthoria in the production of an incandescent electric filament. Theosmium chosen is preferably Feb.10,1914.

in the pure state, orall'owed-with such small percentage of platinum,ruthenium, or-other lilre metal,-sometimes associated with it, as willnot materially lower its point of fusion. I firstprepare a mixture ofosmium (or a suitable compound thereof), thoroxid, or otherthoriumcompound capable under the influence of heat of producing thoroxid, anda substancetwhich operates something after the fashion of a binder orsupport. and which under the influence of'heat resolves itselfpracticallyinto'barbon. To this end,I

prepare a mixture somewhat analogous to a paste and cons sting of,generally stated, osmium, thoroxld andsugar, orinstead of vs I sugar mayemploy collodion or flour paste, or generally. any binding materialwhich under the influences of heat will resolve itself practically intocarbon. .1 use the osmium and thoroxid in a very finely di- 4 videdconditions The described mixture C other suitable mannerto give it thedesired i form. When collodion is employedflt will be necessary todenitrate the filament, after its passage through the die or after ithas been otherwise formed. The presence of the thoria in the paste addsmaterially to the plasticity of the-mass, and consequently to thefacility. with which the filamentary bodies can be formed. therefrom. I

. Without intending to limit myself topro- 1 portions, I may state: thata paste suitable for the manufacture of filaments of osmium and thoroxidmay be prepared'by mixing three parts by .weight of finelydividedmetallic osmium with one part by weight of powdered thoroxid and asuitable quantity of sugar with sufiicient water to causethe'ingredientsto assume a stiff pasty con-' lot dition. The quantity of osmium usedmust be sufficient to form a conductor for the voltage used and aslittle binding material used as will hold the particles together duringthe manufacture of the filament. The thus produced unfinished filamentconsisting of a mixture substantially of osmium, thoroxid andcarbonaceous matter capable upon the application of heat of resolvingitself practically into carbon is then subjected to dry distillation bythe application of he t which resolves the organic matter into 0' .rbonand drives off any volatile constituents present, so that the filamentnow comprises a mixture of carbon, thoroxid and osmium. The carbon isthen removed from the mixture by subjecting the incomplete filamenttothe influence 0 a moderate heat obtained by an electric current in anatmosphere of gases capable of taking up or removing the carbon withoutoxidizing the osmium or deoxidizing the thoroxid. Such an atmosphereshould contain carbonic acid or Water vapor to take up the carbon, but,as these gases would attack the osmium more or less, the atmosphereshould contain a reducing gas, such, for instance, as hydrogen,carbon-monoxid, or hydro-carbons; the simplest composition of such anatmosphere would be hydrogen containing water vapor or carbonic acid, ora mixture of carbonmonoxid and carbonic acid. Such gases may be derived,for instance, from the mixture of gases and vapors incident to theincomplete combustion of illuminating gas procured by the ignitionthereof at the base .of air feed openings of a Bunsen burner,

the said mixture of gases and vapors being collected from the burnertube.

In practice I mount the incomplete filament in a suitable container suchas an incandescent lamp bulb filled with the described gasand then applythe electric current for the elimination of the carbon and theconsolidation and cementation of the particles into a dense, compact andcoherent filament of osmium and thoria, using for that purpose in someinstances a current of one'hundred volts, and developing a heat at whichplatinum would volatilize. If the proportion of oxid is increased thevoltage must be increased, as for instance, if the mixture is one ofequal parts of osmium and thorium I use in its manufacture a current ofthree hundred volts. However the quantity of metal must be sufiicient toact as a conductor of the current after the elimination of the carbon.

Features of my metal-oxid filaments are that they are free from carbon;dense, coherent and elastic and capable of withstanding very hightemperature above that at which platinum volatilizes, and consequentlyare of great efliciency. The completed filaments are mounted andinclosed in bulbs containing a protective gas or, preferably, in avacuum and electrically cemented to the leading-in wires through themedium of an osmium cement as set out in an application executed andfiled herewith. A small quantity of alumina may be added to themixture'from which the filaments are made. Under the heat produced bythe electric current, the alumina is wholly or partially volatilized,the effect of which is to enable the particles of the metal to be morereadily fused or cemented together, and a more dense, compact andelastic filament obtained, the thoria being brought to the surface ofthe filament to which it strongly adheres, with the appearance of anenamel-like coating. When alumina is used, a smaller quantity of thoriais used. Instead of alumina, magnesia, or like oxids of a basiccharacter may be employed,

Having thus described my invention,what I claim as new and desire tosecure by Letters Patent is:

1. An incandescent filament for electric lamps, comprising a stableelectrically'conducting mixture of a metal of the platinum group, ametal oxid and yttrite earth, s b- 'stantially as set forth.

2. The herein described process ofmaking incandescent filaments forelectric lamps, which consists in subjecting a composite body comprisingcarbon,,a metal and a metallic oxid to dry distillation and to theaction of an electric current in an atmosphere of gases which combinewith and remove the carbon, but which is inert with respect to the metaland the metallic oxid, and

.by the action of the electric current cementing the particles into adense coherent elastic filament substantially as set forth.

3. The herein described process of making;

incandescent filaments for electric lamps which consists in associatingcarbonaceous material, a metal and a metallic oxid, distilling off thevolatile constituents of the carbonaceous matter, and finally removingthe carbon by subjecting the material to the action of an electriccurrent in an atmosphere of gases'which combine with the carbon butwhich is inert with respect to the metal and by the action of electriccurrent causing the particlesto cohere substantially as set forth.

4. The process of making incandescent filaments for electriclamps, whichconsists in forming a paste containing carbonaceous matter, a metaland ametallic oxid, forming said paste into the shape of the desired in-.candescent, distilling off. the volatile constituents of thecarbonaceous matter, and" Y which unites with the jecting the same asset forth.

5. The process of making incandescent filaments for eiectric lamps,whichconsistsiriforming a paste of collodion, ametal and a metallic oxid,forming the incandescent body therefrom, denitrating the collodion andsubjecting the same to the action of the electric current in thepresence of a gas carbon and which will be inert to the meta 2 6. .Thehereiii described process of making a filament for incandescent electriclamps from a paste of osmium, thoria, and a binding material, consistingin molding the paste into a suitable wire or thread like form, subto drydistillation and eliminating the carbon by the heat of an electriccurrent passing through the filament in the presence of a suitable gas,and by the action of the electric current causingthe particles to cohereinto a dense coherent and elastic incandescent filament substantially asset forth.

7 The herein described process of making a filament for incandescentelectric lamps from a paste of osmium, thoria, alumina and a bindingmaterial, consisting in molding the paste into a suitable wire or threadlike form, subjecting the same to dry distillation in a protective gasand eliminating the carbon by the heat of an electric current passingthrough the filament'in the'presence of a suitable gas, and by theactionof the electric current causing the particles to cohere into adense coherent and elastic incandescent filament substantially as setforth.

8. The process of making a filament for incandescent electric lamps,which consists in forming a paste, containing rare earth, a carbonaceousbinding material, and metal which fuses at a higher temperature than the-fusing point of platinum, molding the paste into a suitable filamentaryform, subjecting the same .to dry distillation, and

eliminating the carbon by the heat of anelectric current passin throughthe filament in the presence 0 a suitable gas, and, by the actionof theelectric current, causing the particles to cohere into a dense, coherentand elastic incandescent filament; substantially as set forth.

9. The process of making a filament for incandescent electric lamps,which consists informing a paste, containing rare earth, a'basic OXld, acarbonaceous binding material, and-a metal which fuses at a highertemperature than the fusing point of platinum, molding the paste into asuitable wire or thread-like form, subjecting the same to drydistillation, and eliminating the carbon by the heat of'an electriccurrent passing through the filament in the presence ofasuitable gas,and, by the action of the electric current, causing the particles tocohere into a dense, coherent and elastic filament; substantially as setforth.

Signed this 27th day of J lily 1898.

. DR. CARL AUER ,VON WELSBACH. Witnesses:

' Lunwm HAITINGER,

Dr. Anon GALLIA.

incandescent

